And william h



' (No Model.)

W. &-. W. H. ROGERS;

MANUFACTURE OF PLANISHED SHEET IRON.

No. 380,822. PatentedApr.10,"1888.

Ihsrrnn STATES PATENT Orrrcn.

, WILLIAM ROGERS, OF PITTSBURG, PENNSYLVANIA, AND \VILLIAM H.

. ROGERS, OF \VHEELING, WEST VIRGINIA.

MANUFACTURE OF PLANISHED SHEET IRON.

SPECIFICATION forming part of Letters Patent No. 380,822. dated April 10, 11.888.

Application filed March 9, 1887.

To all whom it may concern-.-

Be it known that we, WILLIAM Roanns, of Pittsburg, in the county of Allegheny and State of Pennsylvania, and WILLIAM H. Roenm, of lVheeling, in the county of Ohio and State of West Virginia, have invented a new and useful Improvement in the Manufacture of Russia or Planished Sheet-Iron; and we do hereby declare the following to be a full, clear, and exact description thereof.

Our invention relates to the manufacture of what is known in the art as Russia sheetiron, this sheet-iron having a polished surface or skin which protects it from rusting, and at the same time adds greatly to its appearance, so that it is in great demand for the manufacture of stoves, stove-pipe, and other light sheet-metal ware.

It is well known thatin the rolling of sheetiron at scale or surface of metallic oxide is formed on the surface of the rolled sheet, this scale adhering only partially to the metallic iron; and in case the sheet is heated, or is exposed for any long period, the scale either becomes loosened from the surface of the metal and a new surface of oxide is formed thereon, or the oxide gradually penetrates into the body of the sheet, as the scale is not permanently attached to the body of the sheet and does not sufficiently protect it. It is well known, however, that metallic oxide-such as the scale formed 011 and falling from the sur' face of blooms or rolled metal during the rolling operation1's not affected by the atmosphere, and that it may be exposed for a long period in the presence of moisture without losing its color or being further affected thereby. In the manufacture of finished sheetironsuch as the ordinary American polished or imitation Russia sheet-iron it has been eustomary to remove this scale from the body of the sheet by pickling operation, the acid eating off the scale and exposing the metallic body of the sheet, and by suitable means a coating being formed on the surface of the pickled sheet, this coating acting to some extent to protect the metal from further oxidation; but the sheet metal heretofore manufac tured is found to be less durable than the genuine imported Russia sheet-iron. It is believed that the best protection to the surface Serial No. 230,211. (No model.)

of the sheet is to have permanently united thereto a coating or hide composed largely, if not entirely, of the black magnetic oxide of iron, as such oxide, having absorbed the maxiv mum quantity of oxygen, has no tendency to undergo a further change, which is the great objection to most of the American made Russia iron.

The object of our invention is to utilize the oxide or scale coating formed on the sheet during the rolling by increasing the thickness of the scale coating and changing its condition to that of the magnetic oxide and uniting this oxide coating securely to the sheet. This we accomplish by inclosing the sheets as they come from the rolls in a box, so that a certain amount of air may have access to the sheets, placing between the sheets a layer of fine charcoal, and heating said box and contents to about a red heat, and while hot hammering the sheets in the box, then reheating the sheets in an air-tight box and hammering the same in the box to unite the coating securely to the sheets, as will be more fully hereinafter set forth.

To enable others skilled in the art to practice our invention, we will describe the same more fully, referring to the accompanying drawing, which shows a perspective View of the inclosing sheet-metal box containing the pack of sheet metal to be treated.

In practicing our invention a sheet-metal box is formed capable of holding about forty to sixty sheets and so constructed as to admit a small amount of air.

The box may be of any'desired form, that shown in the drawing being well adapted for the purpose. This box is made with its sides a and bottom from one sheet of metal, in the manner well known tothose skilled in the art, the upper edges of the sides being bent over, as at a, to form a seam with the lid or cover I) when the latter is put in place after the sheets have been laid in the box. The ends of the box are bent outward, as at a, so that when the lid or cover b is slid in under the edges a of the sides these ends can be bent over the end of the lid, as at a. The sides and end seams thus formed allow, during the heating of the box and contents, sufficient air to enter the box to accomplish the desired. purposes,

and when the box is placed under the hammer the seams a and a.will be forced down on the boX, closing it, so that the air does not have access to the contents of the box during the hammering operation.

The sheets of metal are laid in the box, a sprinkling of charcoal being placed between each sheet for the purpose of preventing the sheets from rubbing on each other and thus grinding off the scale, and to prevent any possibility of the sheets welding together when heated. After from forty to sixty sheets have been so placed in the-box the cover or top of the latter is secured in place and the whole charged in a suitable heating-furnace, when the box is raised to a red heat and kept for about fifteen or twenty minutes. During this heating operation the air passing in on the hot iron still further oxidizes the same and increases the thickness of the coating or hide, and at the same time causes the coating to form an intimate union with the metal, so that when the box and contents are taken out while hot and hammered the hide or oxide coating will be fastened to the metal of the sheets, so that it will not scale off. This hammering operation is commenced upon the box while the metal is hot and continued until the metal has cooled to a black heat, the hammer preferably striking quick sharp blows over the surface of the box. The sheets are held together by the box so that they do not rub upon each other and become distorted by the hammering operation. When the hammering operation is completed and thesheets cooled, the latter are taken from the box and carefully examined, those on the outside the pack and those in the pack which show an irregular and imperfect coating being laid aside, to be again subjected to the treatment heretofore described, the remainder being placed in an air-tight box with a sprinkling of charcoal between each sheet; and for the purpose of cutting off all access of oxygen or air to the sheets and neutralizing the effect of the carbon on the oxide coating of the sheets during the heating operation the sides and ends of the box are packed with wet wood, wetsawdust, or sawdust soaked with oil. The box and its contents are then closed securely, so as to be as near air-tight as possible, and charged into a suitable furnace, where it is raised to a red heat and kept for some time, when the box is taken out hot and hammered until the sheets are at a black heat. After this final hammering it will be found that the sheets are covered with a uniform coating,

, which is highly polished and permanently attached to the sheet, so that itv will not peel off.

The effect of the wet wood or sawdust on the sheets is not yet determined; but we think the steam produced by the heating of the same neutralizes the reducing effect of the charcoal on the sheet, and in some way produces the necessary change in the nature of the coating, so as to get a substantially black oxide coating. As the sheets are separated by the carbonaceous material, there is no liability of.

their adhering to each other when subjected to the hammering operation at a high heat; and this carbonaceous material acts in connection with the force of the blows to which the packs of sheets in the box are subjected, to polish the outer surface of the oxide skin on the sheets and impart a fine polished surface thereto, while at the same time this carbonaceous material between the sheets acts to impart to the sheets formed the mottled appearance which is found in the genuine Russia sheet metal, the sheets being rendered slightly uneven on account of the carbonaceous mate rial between the sheets, which cannot practically be held in a perfectly smooth layer or a layer of even thickness between the sheets. The size of these slight indentations imparting the mottled appearance to the sheets may also be varied to some extent by the size of the carbon particles employed between the sheets, coarse particles increasing this mottled effect. Practical use has shown that the oxide surface may in this manner be permanently secured to the body of the sheet, and that a highlypolished surface maybe formed on the sheets, which is permanent and which adds greatly to the appearance thereof. As the sheet metal is not subjected to the ordinary pickling operation and no acid is employed in the treatment thereof, it is evident that the metal of the sheets is not liable to rust under the surface of the protective coating or skin formed thereon, and that for this reason a much more durable surface for and polish to the sheetmetal is obtained. The cost of treating the sheets in the manner above described is not great, requiring only the inclosing of them in the sheet-metal box, the heating of the box, and the hammering operation, which is much more simple than the ordinary treatment by means of which a polished protective coating has heretofore been formed on sheet metal. WVe also find that the quality of metal is greatly improved by our method of treatment.

WVhat we claim as our invention, and desire to secure by Letters Patent, is

1. The herein-described process of forming a protective coating on sheet metal, consisting in heating the sheets while permitting the access of oxygen thereto, so as to form an oxide coating thereon or increase the coating thereof, hammering said sheets while in a heated condition, and finally reheating the sheets to a red heat while protected from the atmosphere, and subjecting the sheets while so protected and heated to a hammering operation, substantially as set forth.

2. The herein-described step in the art of forming a protective coating on sheet metal, consisting in taking ordinary sheets of metal and heating them,while permitting the access of oxygen thereto to increase the thickness of the oxide coating thereon, and then hammering the sheets while hot and inclosed in a box, substantially as set forth.

3. The herein-described step in the art of forming a protective coating on sheet metal, consisting in inclosing the ordinary sheets of metal in a box, heating said box, While permitting the access of asmall amount of air to the sheets therein, and then hammering said box and the contents while hot, substantially as set forth.

4. The herein-described step in the art of forming a protective coating on sheet metal, consisting in inclosing sheets having an oxide coating thereon in an air-tight box, heating the same, and finally hammering the box and contents while hot, substantially as set forth.

5. The herein-described step in the art of 

